DownloadRelationTask.java

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.gui.dialogs.relation;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.io.IOException;
import java.util.Collection;

import javax.swing.SwingUtilities;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.data.osm.DataSetMerger;
import org.openstreetmap.josm.data.osm.Relation;
import org.openstreetmap.josm.gui.DefaultNameFormatter;
import org.openstreetmap.josm.gui.ExceptionDialogUtil;
import org.openstreetmap.josm.gui.PleaseWaitRunnable;
import org.openstreetmap.josm.gui.layer.OsmDataLayer;
import org.openstreetmap.josm.io.OsmServerObjectReader;
import org.openstreetmap.josm.io.OsmTransferException;
import org.openstreetmap.josm.tools.CheckParameterUtil;
import org.xml.sax.SAXException;

/**
 * The asynchronous task for fully downloading a collection of relations. Does a full download
 * for each relations and merges the relation into an {@see OsmDataLayer}
 *
 */
public class DownloadRelationTask extends PleaseWaitRunnable {
    private boolean cancelled;
    private Exception lastException;
    private Collection<Relation> relations;
    private OsmDataLayer layer;
    private OsmServerObjectReader objectReader;

    /**
     * Creates the download task
     *
     * @param relations a collection of relations. Must not be null.
     * @param layer the layer which data is to be merged into
     * @throws IllegalArgumentException thrown if relations is null
     * @throws IllegalArgumentException thrown if layer is null
     */
    public DownloadRelationTask(Collection<Relation> relations, OsmDataLayer layer) throws IllegalArgumentException{
        super(tr("Download relations"), false /* don't ignore exception */);
        CheckParameterUtil.ensureParameterNotNull(relations, "relations");
        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
        this.relations = relations;
        this.layer = layer;
    }

    @Override
    protected void cancel() {
        cancelled = true;
        synchronized(this) {
            if (objectReader != null) {
                objectReader.cancel();
            }
        }
    }

    @Override
    protected void finish() {
        if (cancelled)
            return;
        if (lastException != null) {
            ExceptionDialogUtil.explainException(lastException);
        }
    }

    @Override
    protected void realRun() throws SAXException, IOException, OsmTransferException {
        try {
            final DataSet allDownloads = new DataSet();
            int i=0;
            getProgressMonitor().setTicksCount(relations.size());
            for (Relation relation: relations) {
                i++;
                getProgressMonitor().setCustomText(tr("({0}/{1}): Downloading relation ''{2}''...", i,relations.size(),relation.getDisplayName(DefaultNameFormatter.getInstance())));
                synchronized (this) {
                    if (cancelled) return;
                    objectReader = new OsmServerObjectReader(relation.getPrimitiveId(), true /* full download */);
                }
                DataSet dataSet = objectReader.parseOsm(
                        getProgressMonitor().createSubTaskMonitor(0, false)
                );
                if (dataSet == null)
                    return;
                synchronized (this) {
                    if (cancelled) return;
                    objectReader = null;
                }
                DataSetMerger merger = new DataSetMerger(allDownloads, dataSet);
                merger.merge();
                getProgressMonitor().worked(1);
            }

            SwingUtilities.invokeAndWait(
                    new Runnable() {
                        public void run() {
                            layer.mergeFrom(allDownloads);
                            layer.onPostDownloadFromServer();
                            Main.map.repaint();
                        }
                    }
            );
        } catch (Exception e) {
            if (cancelled) {
                System.out.println(tr("Warning: ignoring exception because task is cancelled. Exception: {0}", e
                        .toString()));
                return;
            }
            lastException = e;
        }
    }
}